JP7286373B2 - Target detection device, system, program and method - Google Patents

Description

The present disclosure relates to technology for detecting moving targets using FMCW radar.

A technique for detecting a target using an FMCW radar is disclosed in Patent Document 1 and the like. As the frequency of the beat signal between the frequency-swept transmitted signal and the received signal reflected from the target is measured lower/higher, the target distance is measured shorter/longer.

JP-A-11-271429

In Patent Literature 1, in order to detect a moving target, beat signals are frequency-converted in different transmission and reception cycles, and target distance spectra are compared. However, when there is a moving target and a stationary target, it is difficult to distinguish the moving target from the stationary target because the stationary target overlaps the moving target in the target distance spectrum. is. Even when there are no moving targets but only stationary targets, the beat signal is frequency-converted in each transmission/reception cycle, making it difficult to reduce the computational load, storage capacity, and power consumption. .

Therefore, in order to solve the above problems, the present disclosure aims to distinguish a moving target from a stationary target in detecting a moving target, thereby reducing computational load, storage capacity, and power consumption.

In order to solve the above problem, a difference signal between beat signals of different transmission and reception cycles is calculated, and the presence or absence of a moving target is detected based on the intensity of the difference signal. It is not necessary to frequency-convert beat signals with different transmission/reception cycles and detect the presence or absence of a moving target based on the spectrum of the target distance. Here, for a moving target, since the beat signals of different transmission and reception cycles change with time, the strength of the difference signal becomes a finite value. However, for a stationary target, the intensity of the difference signal is almost zero because the beat signals of different transmission and reception cycles do not change with time.

Specifically, the present disclosure includes a beat signal acquisition unit that acquires a beat signal between transmission and reception signals of an FMCW radar, a difference signal calculation unit that calculates a difference signal between the beat signals of different transmission and reception cycles, and the difference signal is greater than or equal to a predetermined signal strength, detecting the presence of a moving target within the detection distance range, and detecting the presence of the moving target within the detection distance range when the strength of the differential signal is lower than the predetermined signal strength and a moving target detection unit that detects the absence of a moving target.

Further, the present disclosure is a target detection system including the target detection device described above and the radar transmitting/receiving device of the FMCW radar.

Further, the present disclosure includes a beat signal acquisition step of acquiring a beat signal between transmission and reception signals of an FMCW radar, a difference signal calculation step of calculating a difference signal between the beat signals of different transmission and reception cycles, and a difference signal strength When the intensity of the differential signal is equal to or greater than a predetermined signal intensity, the presence of the moving target is detected within the detection distance range, and when the intensity of the difference signal is lower than the predetermined signal intensity, the moving target is within the detection distance range. and a moving target detection step of detecting the absence of a target object detection program for causing a computer to sequentially execute a moving target object detection step.

Further, the present disclosure includes a beat signal acquisition step of acquiring a beat signal between transmission and reception signals of an FMCW radar, a difference signal calculation step of calculating a difference signal between the beat signals of different transmission and reception cycles, and a difference signal strength When the intensity of the differential signal is equal to or greater than a predetermined signal intensity, the presence of the moving target is detected within the detection distance range, and when the intensity of the difference signal is lower than the predetermined signal intensity, the moving target is within the detection distance range. and a moving target detection step of detecting the absence of the target.

According to these configurations, in detecting a moving target, it is possible to distinguish a moving target from a stationary target and reduce computational load, storage capacity, and power consumption.

Further, according to the present disclosure, the moving target detection unit rotates without moving within the detection distance range when the beat signals of the different transmission and reception cycles have the same beat frequency and different beat phases. Alternatively, it is a target detection device characterized by detecting the presence of a vibrating rotating/oscillating target.

Even for a rotating/oscillating target whose target distance does not change, the intensity of the difference signal becomes a finite value because the beat signals of different transmission and reception cycles change with time. Therefore, rotating/oscillating targets cannot be distinguished from moving targets based solely on the strength of the difference signal. However, according to this configuration, before frequency conversion of the difference signal or the beat signal, it is possible to distinguish the rotation/vibration target from the moving target based on the fact that the beat frequencies of different transmission and reception cycles are the same.

Further, according to the present disclosure, when detecting that the moving target exists within the detection distance range, the moving target detection unit frequency-converts the difference signal or the beat signal to detect the moving target. When it is detected that the moving target does not exist within the detection distance range, the frequency conversion of the difference signal or the beat signal is stopped, and the moving object The target detection device is characterized in that the measurement of the target distance is stopped.

According to this configuration, since the difference signal or the beat signal is frequency-converted only when the moving target is detected, the calculation load, storage capacity and power consumption can be reduced.

Further, according to the present disclosure, the moving target detection unit rotates or vibrates without moving within the detection distance range when the moving target distances in the different transmission/reception cycles are the same. Detecting the presence of a target, and detecting the presence of the moving target moving within the detection distance range when the moving target distances in the different transmission/reception cycles are different. It is a target detection device.

Even for a rotating/oscillating target whose target distance does not change, the intensity of the difference signal becomes a finite value because the beat signals of different transmission and reception cycles change with time. Therefore, rotating/oscillating targets cannot be distinguished from moving targets based solely on the strength of the difference signal. However, according to this configuration, after the frequency conversion of the difference signal or the beat signal, it is possible to distinguish the rotation/vibration target from the moving target on the basis that the moving target distances of different transmission/reception cycles are the same. .

Further, the present disclosure is characterized in that the moving target detection unit adjusts the sampling frequency and modulation frequency for the difference signal or the beat signal, and adjusts the measurement resolution and measurement range for the moving target distance. It is a target detection device.

According to this configuration, by setting the sampling frequency of the difference signal or beat signal to a low frequency, the measurement resolution is improved at short distances and long distances without increasing the order of frequency conversion of the difference signal or beat signal. can be made By setting the modulation frequency of the difference signal or beat signal to low/high frequency, that is, by setting the lower limit of the measurement range to short distance/long distance, the order of frequency conversion of the difference signal or beat signal Measurement resolution can be improved at near/far distances without increasing .

Further, in the present disclosure, the moving target detection unit discards and does not output the moving target distance that is not included within the predetermined distance range, and adopts the moving target distance that is included within the predetermined distance range. It is a target detection device characterized by outputting.

According to this configuration, when only the short distance/long distance is to be detected, or when there is a noise source in the long distance/short distance, only the short distance/long distance can be adopted and output.

In this way, the present disclosure can distinguish moving targets from stationary targets and reduce computational load, storage capacity, and power consumption when detecting moving targets.

1 is a diagram showing a configuration of a target object detection system of the present disclosure; FIG. It is a figure which shows the procedure of the target object detection process of this indication. It is a figure which shows the specific example of the target object detection process of this indication. It is a figure which shows the specific example of the target object detection process of this indication. It is a figure which shows the specific example of the target object detection process of this indication. It is a figure which shows the specific example of the target object detection process of this indication. It is a figure which shows the structure of the moving target detection part of this indication. FIG. 4 is a diagram showing the output of moving target distance of the present disclosure;

Embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of implementing the present disclosure, and the present disclosure is not limited to the following embodiments.

FIG. 1 shows the configuration of the target object detection system of the present disclosure. A target detection system S includes a target detection device 1 and an FMCW radar transmission/reception device 2 . The target detection device 1 comprises a beat signal acquisition section 11, a difference signal calculation section 12 and a moving target detection section 13, and is installed with the target detection program shown in FIG. The FMCW radar transmitting/receiving device 2 includes a PLL circuit 21, an oscillator 22, a divider 23, an amplifier 24, a low-pass filter 25, a transmitting antenna 26, a receiving antenna 27, an amplifier 28, an amplifier 29, a mixer circuit 30, calibrators 31I, 31Q, A/ It is composed of a D converter 32 and a phase modulator 33 .

The PLL circuit 21 controls the oscillator 22 according to the control signal from the target detection device 1 . The oscillator 22 generates a frequency-swept transmission signal according to the control signal of the PLL circuit 21 . The distributor 23 distributes the frequency-swept transmission signal to the amplifiers 24 and 29 . Amplifier 24 amplifies the frequency-swept transmission signal. The low-pass filter 25 passes only necessary low-frequency components and removes unnecessary high-frequency components from the frequency-swept transmission signal. A transmission antenna 26 emits a frequency-swept transmission signal.

The receiving antenna 27 receives a reflected signal reflected from the target T. Amplifier 28 amplifies the reflected signal reflected from target T. FIG. Amplifier 29 amplifies the frequency-swept transmission signal. A mixer circuit 30 outputs I and Q components IF I and IF Q of the beat signal between the frequency-swept transmitted signal LO and the reflected signal RF reflected from the target T. FIG. The calibrators 31I and 31Q remove frequency components near DC from the I and Q components IF I and IF Q of the beat signal in accordance with the control signal DC CAL of the target detection device 1, and obtain the I and Q components CAL I and IF Q of the beat signal. Keep CAL Q within the dynamic range. The A/D converter 32 A/D-converts the I and Q components CAL I and CAL Q of the beat signal and outputs the I and Q components A/D I and A/D Q of the beat signal. The phase modulator 33 modulates the phases of the frequency-swept transmission signal and the reflection signal reflected from the target T according to the control signal DC CAL of the target detection device 1, and converts the beat signal I and Q components IF I, A frequency component in the vicinity of DC is removed from the IFQ, and the I and Q components CAL I and CAL Q of the beat signal are kept within the dynamic range.

FIG. 2 shows the procedure of target object detection processing according to the present disclosure. A specific example of the target detection process of the present disclosure is shown in FIGS. 3 to 6. FIG. The beat signal acquisition unit 11 acquires the I and Q components A/D I and A/D Q of the beat signal between the transmission and reception signals of the FMCW radar (step S1).

The difference signal calculator 12 calculates the I and Q components SUB I and SUB Q of the difference signal between the I and Q components A/D I and A/D Q of beat signals of different transmission and reception cycles (step S2). Note that step S3 will be described later with reference to FIG. Next, steps S4 to S11 will be described with reference to FIGS. 3 to 6. FIG.

In FIG. 3, when the intensity of the I, Q components SUB I, SUB Q of the difference signal is equal to or greater than the predetermined signal intensity (YES in step S4), the moving target detection unit 13 detects the moving target within the detection distance range. exists (step S5). Then, the moving target detection unit 13 performs frequency conversion on the I and Q components SUB I and SUB Q of the difference signal or the I and Q components A/D I and A/D Q of the beat signal to determine the moving target distance. is measured (step S6).

On the other hand, when the intensity of the I and Q components SUB I and SUB Q of the difference signal is lower than the predetermined signal intensity (NO in step S4), the moving target detection unit 13 detects that a moving target exists within the detection distance range. It detects that it does not (step S7). Then, the moving target detection unit 13 stops the frequency conversion of the I and Q components SUB I and SUB Q of the difference signal or the I and Q components A/D I and A/D Q of the beat signal, and determines the distance of the moving target. is stopped (step S8). After step S8 is executed, steps S9 to S14 are not executed.

Specifically, the beat signal acquisition unit 11 acquires beat signals from reception start times t _R1 and t _R2 to transmission end times t _T1 and t _T2 for each of the first and second transmission/reception cycles. Here, for a moving target, the beat signals in the first and second transmission/reception cycles change with time. On the other hand, for stationary targets, the beat signals in the first and second transmission/reception cycles do not change with time.

3, the difference signal calculator 12 sets the times corresponding to the reception start times t _R1 and t _R2 to 0 and the transmission end times t _T1 and t for the beat signals of the first and second transmission/reception cycles. Let _tB be the time corresponding to _T2 . Then, the difference signal calculator 12 sets the time origins corresponding to the reception start times t _R1 and t _R2 to be the same as described above, and then calculates the difference signal between the beat signals of the first and second transmission/reception cycles.

In the middle part of FIG. 3, a moving target exists within the detection distance range. Here, the beat signals in the first and second transmission/reception cycles change with time. Then, the difference signal calculator 12 maintains the frequency component corresponding to the moving target distance in the difference signal between the beat signals of the first and second transmission/reception cycles. Therefore, the moving target detection unit 13 can detect that the moving target exists within the detection distance range because the strength of the differential signal between the beat signals of the first and second transmission/reception cycles is equal to or greater than the predetermined signal strength. can. Then, the moving target detection unit 13 can perform frequency conversion of the difference signal between the beat signals of the first and second transmission/reception cycles, and measure the moving target distance _dM1 .

As shown in the middle of FIG. 3, when the moving target speed is low, the moving target distances in the first and second transmission/reception cycles are almost equal, and the peak distances of the distance spectra in the first and second transmission/reception cycles are not separated. . As a modification, when the moving target speed is high, the moving target distances in the first and second transmission/reception cycles are significantly different, and the peak distances of the distance spectra in the first and second transmission/reception cycles are separated.

In the lower part of FIG. 3, only stationary targets exist within the detection distance range. Here, the beat signals in the first and second transmission/reception cycles do not change with time. Then, the difference signal calculator 12 removes the frequency component corresponding to the stationary target distance in the difference signal between the beat signals of the first and second transmission/reception cycles. Therefore, the moving target detection unit 13 can detect that the strength of the differential signal between the beat signals of the first and second transmission/reception cycles is lower than the predetermined signal strength and that no moving target exists within the detection distance range. . Then, the moving target detection unit 13 can stop the frequency conversion of the difference signal between the beat signals of the first and second transmission/reception cycles, and stop the measurement of the stationary target distance _dS .

In this way, when detecting a moving target, it is possible to distinguish the moving target from the stationary target. Since the difference signal or the beat signal is frequency-converted only when a moving target is detected, the calculation load, storage capacity and power consumption can be reduced.

In FIG. 4, the moving target detection unit 13 detects that there is a moving target within the detection distance range when the moving target distances in different transmission/reception cycles are different (NO in step S9). step S10). Here, the moving target includes a person, a vehicle, or the like.

In FIG. 5, the moving target detection unit 13 rotates or vibrates without moving within the detection distance range when the moving target distances in different transmission/reception cycles are the same (YES in step S9). The existence of a vibrating target is detected (step S11). Here, the rotation/vibration targets include trees, poles, ventilation fans, walls, and the like. After step S11 is executed, steps S12 to S14 are not executed.

Specifically, the beat signal acquisition unit 11 obtains beat signals from reception start times t _R1 , t _R2 , and t _R3 to transmission end times t _T1 , t _T2 , and t _T3 for each of the first, second, and third transmission/reception cycles. Get the signal. Here, for the rotating/oscillating target, the beat signals of the first, second, and third transmission/reception cycles change with time. On the other hand, the beat signals of the first, second, and third transmission/reception cycles also change with time for the moving target.

As described above, even for a rotating/oscillating target whose target distance does not change, the beat signals in the first, second and third transmission/reception cycles change with time. has a finite value. Therefore, a rotating/oscillating target cannot be distinguished from a moving target based only on the intensity of the difference signal between the beat signals of the first, second, and third transmission/reception cycles.

4 and 5, the difference signal calculator 12 sets the times corresponding to the reception start times t _R1 , t _R2 , and t _R3 to 0 for the beat signals of the first, second, and third transmission/reception cycles. , transmission end times t _T1 , t _T2 , and t _T3 are assumed to be t _B . Then, the difference signal calculator 12 makes the time origins corresponding to the reception start times t _R1 , t _R2 , and t _R3 the same as described above, and calculates the difference signal between the beat signals of the first and second transmission/reception cycles and A difference signal between the beat signals of the second and third transmission/reception cycles is calculated.

In the lower middle part of FIG. 4, a moving target exists within the detection distance range. Here, the beat signals of the 1st, 2nd and 3rd transmission/reception cycles change with time. Then, the difference signal calculator 12 maintains the frequency component corresponding to the moving target distance in the difference signal between the beat signals of the first and second transmission/reception cycles and the difference signal between the beat signals of the second and third transmission/reception cycles. ing. Therefore, the moving target detection unit 13 detects that the strength of the difference signal between the beat signals in the first and second transmission/reception cycles and the strength of the difference signal between the beat signals in the second and third transmission/reception cycles are equal to or greater than the predetermined signal strength, and the detection is performed. The presence of a moving target or the presence of a rotating/oscillating target within the range of distance can be detected. The moving target detection unit 13 detects that the moving target distance _dM1 in the first and second transmission/reception cycles is different from the moving target distance _dM2 in the second and third transmission/reception cycles, and is within the detection distance range. It is possible to detect the presence of moving targets rather than the presence of rotating/oscillating targets.

As shown in the middle and lower part of FIG. 4, when the moving target speed is low, the moving target distances of adjacent transmission/reception cycles are almost equal, and the peak distances of the distance spectra of adjacent transmission/reception cycles are not separated, but slightly The peak distances of the distance spectrum for separate transmit and receive cycles are isolated. As a modification, when the moving target speed is high, the moving target distances in adjacent transmission/reception cycles differ greatly, and the peak distances of the distance spectrums in adjacent transmission/reception cycles are separated, so the transmission/reception cycles are slightly separated. There is no need to detect the peak distance of the distance spectrum of .

In the lower middle part of FIG. 5, a rotation/vibration target exists within the detection distance range. Here, the beat signals of the 1st, 2nd and 3rd transmission/reception cycles change with time. Then, the difference signal calculator 12 calculates the frequency component corresponding to the rotation/vibration target distance in the difference signal between the beat signals of the first and second transmission/reception cycles and the difference signal between the beat signals of the second and third transmission/reception cycles. maintain. Therefore, the moving target detection unit 13 detects that the strength of the difference signal between the beat signals in the first and second transmission/reception cycles and the strength of the difference signal between the beat signals in the second and third transmission/reception cycles are equal to or greater than the predetermined signal strength, and the detection is performed. The presence of rotating/oscillating targets or the presence of moving targets within the distance range can be detected. The moving target detection unit 13 detects that the moving target distance d _R in the first and second transmission/reception cycles is the same as the moving target distance d _R in the second and third transmission/reception cycles, and the detection distance range It is possible to detect the presence of rotating/oscillating targets rather than the presence of moving targets within.

In this way, after frequency conversion of the difference signal or beat signal, the rotational/oscillating target can be distinguished from the moving target based on the fact that the moving target distances in different transmission/reception cycles are the same.

3 to 5, the moving target detection unit 13 performs frequency conversion of the difference signal between the beat signals of the first and second (including the third in FIGS. 4 and 5) transmission and reception cycles, Execute the measurement of the moving target distance. As a modification, the moving target detection unit 13 performs frequency conversion on each of the beat signals of the first and second (including the third depending on FIGS. 4 and 5) transmission/reception cycle, and calculates the moving target distance. measurement may be performed. 3 to 5, the moving target detection unit 13 can reduce calculation load, storage capacity and power consumption. In the modified example, the moving target detection unit 13 can distinguish in which direction the moving target distance changes over time, long distance or short distance.

3 to 5, the difference signal calculator 12 calculates the difference signal between the beat signals of the first and second (including the third in FIGS. 4 and 5) transmission/reception cycles, and detects the moving target. The unit 13 detects when the strength of the difference signal between the beat signals of the first and second (including the third in FIGS. 4 and 5) is equal to or higher than a predetermined signal strength/lower than a predetermined signal strength. To detect the presence/absence of a moving target within a distance range. As a modification, the difference signal calculator 12 calculates a division signal between the beat signals of the first and second (including the third according to FIGS. 4 and 5) transmission/reception cycles, and the moving target detector 13 moves within the sensing distance range when the strength of the division signal between the beat signals of the first and second (and depending on FIGS. 4 and 5, also includes the third) time-varying/not time-varying signals of the transmission and reception cycles Presence/absence of a target may be detected.

In FIG. 6, the moving target detection unit 13 detects the detection distance when the beat frequency is the same and the beat phase is different between the I and Q components A/D I and A/D Q of the beat signals of different transmission and reception cycles. Detect the presence of rotating/oscillating targets that rotate or oscillate without moving within range. Here, the rotation/vibration targets include trees, poles, ventilation fans, walls, and the like. Note that steps S12 to S14 are not executed after FIG. 6 is executed.

Specifically, the beat signal acquisition unit 11 calculates from the reception start times t _R1 , t _R2 , t _R3 , t _R4 to the transmission end times t _T1 , t _T2 , t for each of the first, second, third, and fourth transmission/reception cycles. Acquire the beat signal from _T3 , t to _T4 . Here, for the rotating/oscillating target, the beat frequencies in the 1st, 2nd, 3rd and 4th transmission/reception cycles do not change over time, but the beat phases in the 1st, 2nd, 3rd and 4th transmission/reception cycles change over time. On the other hand, for a moving target, the beat frequencies of the 1st, 2nd, 3rd and 4th transmission/reception cycles change with time, and the beat phases of the 1st, 2nd, 3rd and 4th transmission/reception cycles also change with time.

As described above, even for a rotating/oscillating target whose target distance does not change, the beat frequencies of the first, second, third and fourth transmission/reception cycles do not change over time, but the beat signals of the first, second, third and fourth transmission/reception cycles changes with time, the intensity of the difference signal between the beat signals in the first, second, third and fourth transmission/reception cycles becomes a finite value. Therefore, a rotating/oscillating target cannot be distinguished from a moving target based only on the intensity of the difference signal between the beat signals of the first, second, third, and fourth transmission/reception cycles.

In the lower part of FIG. 6 , the difference signal calculator 12 sets the times corresponding to the reception start times t _R1 , t _R2 , t _R3 , and t _R4 to 0 for each of the beat signals of the first, second, third, and fourth transmission/reception cycles. and _tB is the time corresponding to the transmission end times _tT1 , _tT2 , _tT3 , _tT4 . However, the difference signal calculator 12 sets the time origin corresponding to the reception start times t _R1 , t _R2 , t _R3 , and t _R4 to be the same, and calculates A difference signal is not calculated.

In the lower part of FIG. 6, a rotation/vibration target exists within the detection distance range. Here, the beat frequencies in the 1st, 2nd, 3rd and 4th transmission/reception cycles do not change over time, but the beat phases in the 1st, 2nd, 3rd and 4th transmission/reception cycles change over time. Then, the moving target detection unit 13 detects that the I and Q components at a certain time in the beat signals of the 1st, 2nd, 3rd and 4th transmission/reception cycles change with time as indicated by black circles. Therefore, the moving target detection unit 13 can detect that a rotating/oscillating target exists within the detection distance range instead of a moving target. Furthermore, the moving target detection unit 13 can measure the rotation/vibration speed of the rotation/vibration target based on the temporal change of the I and Q components at a certain time in the beat signals of different transmission/reception cycles.

In this way, rotating/oscillating targets can be distinguished from moving targets based on the fact that the beat frequencies of different transmission and reception cycles are the same before the frequency conversion of the difference signal or the beat signal.

FIG. 7 shows the configuration of the moving target detection unit of the present disclosure. The moving target detection unit 13 detects I and Q components SUB I and SUB Q (shown in FIG. 7) of the difference signal or I and Q components A/D I and A/D Q (not shown in FIG. 7) of the beat signal. .) are adjusted, and the measurement resolution and measurement range are adjusted for the moving target distance (step S3).

Specifically, the moving target detection unit 13 includes mixer circuits 131I and 131Q, low-pass filters 132I and 132Q, decimators/interpolators 133I and 133Q, and a frequency converter . Mixer circuits 131I and 131Q modulate the I and Q components SUB I and SUB Q of the differential signal at a desired modulation frequency. The low-pass filters 132I, 132Q pass only the necessary low frequency components from the I and Q components MOD I, MOD Q of the difference signal. Decimators/interpolators 133I, 133Q sample the I, Q components LPF I, LPF Q of the difference signal at a desired sampling frequency. A frequency converter 134 frequency-converts the I and Q components SAM I and SAM Q of the differential signal.

Here, the frequency measurement resolution is F _S /FFT (F _S is the sampling frequency and FFT is the order of frequency conversion). Therefore, the distance measurement resolution is ((F _S /FFT) x S _T x c ₀ )/(2 x F _W ) (S _T is the sweep time width, c ₀ is the speed of light, and _FW is the sweep frequency width. ). The longest measured distance is ((F _S /2)*S _T *c ₀ )/(2*F _W ).

Therefore, if the measurement range is limited to a short distance, the sampling frequency _FS in the formula for the maximum measurement distance should be reduced, and the distance measurement resolution can be improved. However, if the measurement range is extended to a long distance, the sampling frequency _FS in the formula for the maximum measurement distance can be increased, but the distance measurement resolution cannot be improved. Therefore, when extending the measurement range to a long distance, in order to improve the distance measurement resolution, after changing the lower limit of the measurement range from 0 to a finite value, the maximum measurement distance (from the lower limit of the measurement range) The sampling frequency F _S in the formula should not be too large. Then, in order to change the lower limit of the measurement range from 0 to a finite value, the mixer circuits 131I and 131Q modulate the I and Q components SUB I and SUB Q of the difference signal with desired modulation frequencies, 132Q passes only the necessary low frequency components from the I and Q components MOD I, MOD Q of the differential signal.

By setting the sampling frequency of the difference signal or beat signal to a low frequency in this way, the measurement resolution can be improved at short and long distances without increasing the order of frequency conversion of the difference signal or beat signal. can be done. By setting the modulation frequency of the difference signal or beat signal to low/high frequency, that is, by setting the lower limit of the measurement range to short distance/long distance, the order of frequency conversion of the difference signal or beat signal Measurement resolution can be improved at near/far distances without increasing .

The moving target distance output of the present disclosure is shown in FIG. The moving target detection unit 13 discards and does not output moving target distances that are not within the predetermined distance range (NO in step S12 and step S13). On the other hand, the moving target detection unit 13 adopts and outputs the moving target distance included in the predetermined distance range (YES in step S12 and step S14).

The left column of FIG. 8 shows the case where only a short distance is to be detected (a person, a vehicle, etc.), or the case where there is a noise source (tree, pole, ventilation fan, wall, etc.) at a long distance. Here, the moving target detection unit 13 discards and does not output the moving target distance _dM2 that is not included in the predetermined distance range that is shorter than the target distance threshold _dTh . On the other hand, the moving target detection unit 13 adopts and outputs a moving target distance _dM1 included within a predetermined distance range shorter than the target distance threshold _dTh .

The right column of FIG. 8 shows cases where only long-distance detection targets (humans, vehicles, etc.) are detected, or where there are noise sources (trees, poles, ventilation fans, walls, etc.) in short distances. Here, the moving target detection unit 13 discards and does not output the moving target distance _dM1 that is not included in the predetermined distance range longer than the target distance threshold _dTh . On the other hand, the moving target detection unit 13 adopts and outputs a moving target distance _dM2 included within a predetermined distance range longer than the target distance threshold _dTh .

In this way, only short/long distances can be adopted and output when only short/long distances are to be detected, or when there is a noise source at long/short distances.

For example, by distinguishing the rotation of the ventilation fan inside and outside the elevator or the vibration of the wall from the movement of people inside and outside the elevator, it is possible to prevent erroneous opening and closing of the automatic door of the elevator. Alternatively, by distinguishing the rotation of the ventilation fan or the vibration of the wall inside the emergency staircase from the movement of a person inside the emergency staircase, it is possible to prevent erroneous lighting of the automatic lighting of the emergency staircase.

INDUSTRIAL APPLICABILITY The target object detection device, system, program, and method of the present disclosure can be applied to applications such as detecting a person moving inside or outside an elevator or a person moving inside an emergency staircase.

S: Target detection system T: Target 1: Target detection device 2: FMCW radar transmitter/receiver 11: Beat signal acquisition unit 12: Difference signal calculation unit 13: Moving target detection unit 21: PLL circuit 22: Oscillator 23: Distributor 24: Amplifier 25: Low-pass filter 26: Transmitting antenna 27: Receiving antenna 28: Amplifier 29: Amplifier 30: Mixer circuits 31I, 31Q: Calibrator 32: A/D converter 33: Phase modulators 131I, 131Q: Mixer circuit 132I, 132Q: low-pass filters 133I, 133Q: decimator/interpolator 134: frequency converter

Claims (8)

a beat signal acquisition unit that acquires a beat signal between transmission and reception signals of the FMCW radar;
a difference signal calculation unit that calculates a difference signal in the time domain between the beat signals of different transmission and reception cycles;
detecting the presence of a moving target within a detection distance range when the intensity of the difference signal is equal to or greater than a predetermined signal intensity; and detecting the presence of the moving target within the detection distance range when the intensity of the difference signal is lower than the predetermined signal intensity. a moving target detection unit that detects that the moving target does not exist in
The moving target detection unit rotates or vibrates without moving within the detection distance range when the beat signals of the different transmission and reception cycles have the same beat frequency and different beat phases. Detect presence of target
A target detection device characterized by: a beat signal acquisition unit that acquires a beat signal between transmission and reception signals of the FMCW radar;
a difference signal calculation unit that calculates a difference signal in the time domain between the beat signals of different transmission and reception cycles;
detecting the presence of a moving target within a detection distance range when the intensity of the difference signal is equal to or greater than a predetermined signal intensity; and detecting the presence of the moving target within the detection distance range when the intensity of the difference signal is lower than the predetermined signal intensity. a moving target detection unit that detects that the moving target does not exist in
When detecting that the moving target exists within the detection distance range, the moving target detection unit frequency-converts the difference signal or the beat signal to obtain a moving target that is a distance to the moving target. measuring the target distance, and when it is detected that the moving target does not exist within the detection distance range, stopping the frequency conversion of the difference signal or the beat signal, and stopping the measurement of the moving target distance; do
A target detection device characterized by: When the moving target distances in the different transmission/reception cycles are the same, the moving target detection unit detects that a rotating/vibrating target that rotates or vibrates without moving exists within the detection distance range. is detected, and the presence of the moving target moving within the detection distance range is detected when the moving target distances in the different transmission/reception cycles are different. target detection device. 4. The moving target detection unit adjusts the sampling frequency and modulation frequency for the difference signal or the beat signal, and adjusts the measurement resolution and measurement range for the moving target distance. Target detection device according to. The moving target detection unit discards and does not output the moving target distance that is not included within the predetermined distance range, and adopts and outputs the moving target distance that is included within the predetermined distance range. The target detection device according to any one of claims 2 to 4 . A target detection system comprising: the target detection device according to any one of claims 1 to 5 ; and a radar transmission/reception device for the FMCW radar. a beat signal acquisition step of acquiring a beat signal between transmission and reception signals of the FMCW radar;
a difference signal calculation step of calculating a difference signal in the time domain between the beat signals of different transmission and reception cycles;
detecting the presence of a moving target within a detection distance range when the intensity of the difference signal is equal to or greater than a predetermined signal intensity; and detecting the presence of the moving target within the detection distance range when the intensity of the difference signal is lower than the predetermined signal intensity. a moving target detection step of detecting that the moving target does not exist in the
are executed by the computer in order ,
In the moving target detecting step, when the beat signals of the different transmission/reception cycles have the same beat frequency and different beat phases, the target rotates or vibrates without moving within the detection distance range. Detect presence of target
A target detection program characterized by : a beat signal acquisition step of acquiring a beat signal between transmission and reception signals of the FMCW radar;
a difference signal calculation step of calculating a difference signal in the time domain between the beat signals of different transmission and reception cycles;
detecting the presence of a moving target within a detection distance range when the intensity of the difference signal is equal to or greater than a predetermined signal intensity; and detecting the presence of the moving target within the detection distance range when the intensity of the difference signal is lower than the predetermined signal intensity. a moving target detection step of detecting that the moving target does not exist in the
are prepared in order ,
In the moving target detecting step, when the beat signals of the different transmission/reception cycles have the same beat frequency and different beat phases, the target rotates or vibrates without moving within the detection distance range. Detect presence of target
A target detection method characterized by:

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